Recently, methods of handling charges for energy consumption have been devised, such as supply-demand power contract systems that give rewards and/or penalties to consumers complying with requests from a supplier who supplies power, and time-of-use price systems in which prices specific to time slots are set. Developments have been made with regard to demand response that provides stable energy supply, with the balance between energy supply and energy consumption left to the consumer's decisions. Demand response control, whereby facility devices are controlled so as to correspond to this manner of demand response, can be implemented not only with factories and other specific large-scale facilities, but also with common facility devices in office buildings, households, and the like. This manner of demand response includes systems in which it is presumed that the consumer will accept an increase in charges, and it is up to the consumer to decide the amount of energy that will be consumed by the facility devices. With this manner of system, it is anticipated to occur that there are frequent scenarios in which the consumer must select in real time whether to prioritize suppressing energy consumption or to prioritize the activities of the facility devices.
For example, Japanese Laid-open Patent Publication No. H11-168833 discloses a technique of providing target demand rate display means for displaying the ratio of currently used power to a reference power at the current time, whereby the current state is easily understood at a glance. Japanese Laid-open Patent Publication No. 2005-283731 discloses a technique of outputting a message according to a provider service, which changes depending on the time slot, and notifying a user (a consumer).